Frederick S. Dunn (August 3, 1872 – January 7, 1937) was an American scholar of classical studies and Ku Klux Klan leader.
Born in Eugene, Oregon, he received degrees from the University of Oregon (1892) and Harvard University (1894). He married Anna Maude Matthews in 1895, with whom he had two children.
Dunn taught Latin first at Willamette University and then at the University of Oregon, where he became full professor in 1898. He retired in 1935, having headed the Classics department for most of his tenure. He obtained a national reputation as a classics scholar, publishing extensively with a focus on Roman Era coins and on Julius Caesar.
Outside of academy, Dunn was active in the Masonic Order and served as a lieutenant in the U.S. Army towards the end of World War I, but did not see combat service. He was also the leader, or "Exalted Cyclops", of Eugene Klan No. 3, a Ku Klux Klan group ("klavern"). In the early 1920s, the Klan was particularly powerful in Oregon, with some 35'000 members out of a population of 780'000. It was very active in Eugene, where it had some success in removing Catholics from public office, and Dunn's membership was known at the University of Oregon, where the Klan also agitated, by 1922.
In 2016, following a historians' report on Dunn's history as a Klan leader, the University of Oregon removed Dunn's name from a dormitory named after him, "Dunn Hall".